On Sat, Dec 18, 2010 at 1:04 PM, Mulyadi Santosa <mulyadi.santosa@xxxxxxxxx> wrote: > > Hi Greg... > > On Sun, Dec 19, 2010 at 00:53, Greg Freemyer <greg.freemyer@xxxxxxxxx> wrote: > > Mulyadi, > > > > Raid is separately implemented in both MDRAID and DM. > > Oh s**t, I f**k *p....thanks for the correction...didn't know about MDRAID.... > > > DM (device mapper) is the newer code base that was created for 2.6, but it > > is far less functional than MD. > > I see...so basically DM isn't meant for RAID...? The eventual goal is for DM to grow various levels of raid support. Currently just 0 and 1 (as well as concatenation.) So if someone wants to jump in take on a big project, they could go for Raid 5 in DM. (Personally MDraid is so good, I don't see any real reason to add raid 5 etc. to DM, but I believe that is the goal.) > > ie. DM does not support raid 10, 4, 5, or 6. MDRAID supports all of those > > including multiple varieties of raid 10. > > aha.... but wait, raid 10? or 1+0? Both Raid 10 and Raid 1+0 effectively mean the same. The plus is basically implied unless you want Raid 0+1. I've never seen that call raid 01. I think the use varies on how you build the array. If you first build a stripeset, then mirror them as 2 separate steps, then use 1+0. If on the otherhand you make a single call to mdadm (as an example) and tell it do do the work in one step, then it is raid 10. The advantage of raid 10 over 1+0 is mdadm has several ways internally to build a raid 10 whereas there is basically only one way to build a 1+0.. Read about --layout for mdadm http://linux.die.net/man/8/mdadm Greg > -- > regards, > > Mulyadi Santosa > Freelance Linux trainer and consultant > > blog: the-hydra.blogspot.com > training: mulyaditraining.blogspot.com -- Greg Freemyer Head of EDD Tape Extraction and Processing team Litigation Triage Solutions Specialist http://www.linkedin.com/in/gregfreemyer CNN/TruTV Aired Forensic Imaging Demo - http://insession.blogs.cnn.com/2010/03/23/how-computer-evidence-gets-retrieved/ The Norcross Group The Intersection of Evidence & Technology http://www.norcrossgroup.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
